The detection and discrimination of types of aerosols has utility in public health monitoring, occupational health monitoring, biological and chemical defense sensing, and industrial production monitoring. For many of these applications it is desirable to be able to measure and discriminate aerosols that form a minority population of an ensemble aerosol, which may include organic, inorganic, and/or biological particles, as well as other particles known in the art. In these cases it is often useful to measure individual aerosol particles for detection and classification.
Prior aerosol instruments typically measure very small concentrations of aerosols, such as single aerosol particles in a liter of air, in a background of a very large number of ambient aerosol particles, which may be as numerous as hundreds to thousands of particles per liter of air. Some instruments of this type simply measure the particle size through optical scattering or aerodynamic means. Other instruments use fluorescence or scattering at multiple visible wavelengths to classify particles. Many of these instruments measure individual aerosol particles one at a time in a very rapid fashion rather than measuring mixtures, or ensembles, of aerosol particles.
Thus, there is a need for an in-situ aerosol sensor that can detect and classify multiple types of aerosols in a rapid, inexpensive manner.